Employees are considered to be the most valuable assets of organization. In order to valuably utilize that asset their commitment level should be increased; and leadership style is one of the determinants which can influence the commitment level of the workforce. The purpose of this study is to examine the impact of transformational leadership style on employee affective commitment in banking sector. 4 banks and 293 employees of the banks were selected for study purpose. Findings of the study show that there is significant and positive relation between transformational leadership and employees’ affective commitment. The study provides a tool to retain the employee by stimulating their level of affective commitment to the organization. This study recommended that leaders have to adapt transformational leadership style in order to increases the level of affective commitment in the employees of banking sector and provides practical implications for researches interested in exploring the employees commitment with respect to leadership in broader context.